The diagnostic value of magnetic resonance imaging measurements for assessing cervical spinal canal stenosis

OBJECT

The authors investigated the relevance of 2D MRI measurements for the diagnosis of critical cervical spinal canal stenosis. Among patients who had sustained a minor cervical spine trauma, they compared MRI measurements of the cervical spine between those with acute cervical spinal cord injury (CSCI) and those without. They also investigated the correlation between the MRI measurements and the severity of CSCI as well as classification accuracy concerning the diagnosis of critical spinal canal stenosis for acute CSCI after a minor trauma.

METHODS

The authors conducted a single-center retrospective radiological case-control study of patients who had sustained CSCI after a minor trauma to the cervical spine from January 2000 to August 2010. The controls were patients who had sustained a cervical trauma without clinical or radiological signs of cervical spinal cord pathology.

On axial T2-weighted MR images, the following were measured: the transverse spinal canal and cord area, the transverse and sagittal cord diameter, and the sagittal canal diameter of the cervical spine (C3–7). Using these measurements, the authors calculated the cord-canal-area ratio by dividing the transverse cord area by the transverse canal area, the space available for the cord by subtracting the sagittal canal diameter from the sagittal cord diameter, and the compression ratio by dividing the transverse cord diameter by its sagittal diameter.

The severity of CSCI was assessed by using the motor index scores of 10 key muscles at different time points (initially, 1, 3, and 12 months after injury) obtained from the clinical records.

The intra- and interobserver reliability of the MRI measurements, intra- and intergroup differences, and correlations between variables were also investigated. Receiver operating characteristic curves were calculated for evaluating the classification accuracy of the imaging variables for CSCI.

RESULTS

Data for 52 CSCI patients and 77 control patients were analyzed. The intra- and interobserver reliability regarding the MRI measurements ranged from good (0.72) to perfect (0.99). Differences between the CSCI group and the control group were significant (p < 0.001) for all parameters, except for the cord area. The most prominent differences between the groups existed for the spinal canal area, cord-canal-area ratio, and space available for the cord. The classification accuracy was best for the cord-canal-area ratio and the space available for the cord; areas under the curve were 0.99 (95% CI 0.97–1.0) and 0.98 (95% CI 0.95–0.99), respectively. There was no significant (p > 0.05) correlation between any of the imaging parameters and the motor index score at any time point.

CONCLUSIONS

The cord-canal-area ratio (> 0.8) or the space available for the cord (< 1.2 mm) measured on MR images can be used to reliably identify patients at risk for acute CSCI after a minor trauma to the cervical spine. However, there does not seem to be any association between spinal canal imaging characteristics and the severity of or recovery from CSCI after a minor trauma.

Charcot arthropathy of the spine in spinal cord injured individuals with sacral deafferentation and anterior root stimulator implantation

AIMS

To investigate the occurrence of Charcot spinal arthropathy (CSA) after sacral deafferentation (SDAF) and sacral anterior root stimulation (SARS) of the bladder in patients suffering from neurogenic lower urinary tract dysfunction (NLUTD) as a result of spinal cord injury (SCI).

METHODS

Retrospective evaluation of patients who had undergone SDAF/SARS at a single SCI rehabilitation centre. The occurrence rate of stimulation dysfunction was determined, and the medical records and radiological images of the included patients were examined for CSA. The diagnosis of CSA was based on radiological criteria. The occurrence rate of CSA was estimated for all SARS patients and for those with SARS dysfunction, and the odds ratios (OR) for the occurrence of CSA were calculated.

RESULTS

In 11/130 SARS patients (8%), CSA was observed a median 8 years (95% CI 5-16 years) after SDAF/SARS or a median 21 years (95% CI 9-41 years) after SCI had occurred. The median follow-up time was 14 years (range 6-25 years). The proportion of patients with CSA was significantly (P = 0.036) greater in patients with SARS dysfunction (7/41) than in patients without SARS dysfunction (4/89). The odds of CSA were four times greater (OR 4.3, 95% CI 1.0-21.5) in patients with SARS dysfunction compared to those without. Furthermore, the odds of CSA were 20 times greater (OR 20.2, 95% CI 8.4-47.0) in patients with SARS compared to those without.

CONCLUSIONS

Charcot spinal arthropathy should be considered a potential long-term complication of SDAF/SARS, and spinal instability is a possible reason for SARS dysfunction.

Functional outcome of supratrigonal cystectomy and augmentation ileocystoplasty in adult patients with refractory neurogenic lower urinary tract dysfunction

AIMS

To investigate the functional outcome after supratrigonal cystectomy and augmentation ileocystoplasty in adult patients with refractory neurogenic lower urinary tract dysfunction (NLUTD).

METHODS

Retrospective follow-up investigation in a single spinal cord injury rehabilitation center. In 29 patients, urodynamic data before and after supratrigonal cystectomy and augmentation ileocystoplasty, clinical outcome and post-operative complications were evaluated.

RESULTS

The median age of the 29 patients at the time of surgery was 31 years, a median 14 years after NLUTD had occurred. At the last follow-up visit (median 2.4, range 0.4-9.0 years post-operatively), 20/29 patients (69%) were continent compared to 2/29 pre-operatively (P = 0.001). Furthermore, 16 patients required no or less detrusor relaxation therapy after augmentation ileocystoplasty. Augmentation cystoplasty resulted in a significant (P = 0.001) increase in the median bladder capacity (from 240 ml to 500 ml) and compliance (from 13 ml/cm H2 O to 50 ml/cm H2 O). The median maximum detrusor pressure had decreased significantly (P = 0.001) from 38 cm H2 O to 15 cm H2 O. Significantly (P = 0.001) fewer patients presented with a risk for renal damage (1 vs. 15 with maximum detrusor pressure >40 cm H2 O and 1 vs. 12 with detrusor compliance <20 ml/cm H2 O) at the last follow-up. The following complications were observed in 11/29 (38%) patients: paralytic and obstructive ileus, impaired bowel function, bladder stones, dehiscence, metabolic acidosis and autonomic dysreflexia.

CONCLUSIONS

Protection of renal function, adequate bladder capacity and low detrusor pressure can be achieved using supratrigonal cystectomy and augmentation ileocystoplasty in patients suffering from refractory NLUTD.

Testicular resistive index determined by Doppler ultrasonography in men with spinal cord injury - a case series

In this case series, the testicular resistive index was determined in men with spinal cord injury. In ten men participating in our fertility programme, the peak systolic and end-diastolic velocity of centripetal testicular arteries was measured in triplicates by Doppler ultrasonography to calculate the testicular resistive index. Furthermore, the right and left testicular volume was determined by ultrasonography, blood samples were obtained for hormonal evaluation, and sperm analysis was performed according to the WHO guidelines. The median testicular resistive index measured 0.69 and was significantly (P < 0.001) greater than the reported cut-off value of 0.6. The spermiograms were characterised by normal sperm count but decreased sperm motility and plasma membrane integrity. The median right and left testicular volume was significantly (P < 0.01) smaller compared to the volumes measured in able-bodied adult males without scrotal pathology and measured 8.4 ml and 7.2 ml respectively. There was a significant (P = 0.005) correlation (rs  = 0.81) between testicular resistive index and sperm concentration. However, no correlations were observed between testicular resistive index and other variables. The testicular resistive index in men with spinal cord injury was significantly greater than 0.6. Measuring the testicular resistive index may represent a useful additional parameter in the assessment of infertility in spinal cord-injured men.

Characteristics and surgical management of neuropathic (Charcot) spinal arthropathy after spinal cord injury

BACKGROUND CONTEXT

Neuropathic (Charcot) spinal arthropathy (CSA) is a rare but progressive and severe degenerative disease that develops in the absence of deep sensation, for example, after spinal cord injury. The diagnosis of CSA is often delayed as a result of the late onset or slow progression of the disease and the nonspecific nature of the reported clinical signs. Considering risk factors of CSA in combination with the common clinical signs may facilitate timely diagnosis and prevent severe presentation of the disease. However, there is a lack of data concerning the early signs and risk factors of CSA. Furthermore, the complications and outcomes after surgical treatment are documented insufficiently.

PURPOSE

To investigate the early signs and risk factors of CSA after spinal cord injury, as well as the complications and outcome after surgical treatment.

STUDY DESIGN

Retrospective case series from a single center.

PATIENT SAMPLE

Twenty-eight patients with 39 Charcot joints of the spine.

OUTCOME MEASURES

Clinical signs, radiological signs, risk factors, and complications.

METHODS

The case histories and radiological images of patients suffering from CSA were investigated.

RESULTS

The first clinical symptoms included spinal deformity, sitting imbalance, and localized back pain. Long-segment stabilization, laminectomy, scoliosis, and excessive loading of the spine were identified as risk factors for the development of the disease. Postoperative complications included implant loosening, wound healing disturbance, and development of additional Charcot joints. All patients were able to return to their previous levels of activities.

CONCLUSIONS

Radiological follow-up of the entire thoracic and lumbar spine should be performed in paraplegic patients. Risk factors in combination with typical symptoms should be considered to facilitate early detection. Functional restoration can be achieved with appropriate surgical techniques.

Short-segment posterior instrumentation combined with anterior spondylodesis using an autologous rib graft in thoracolumbar burst fractures

BACKGROUND AND PURPOSE

There are very few data concerning the outcome after short-segment posterior stabilization and anterior spondylodesis with rib grafts in patients suffering from unstable thoracolumbar burst fractures. We have therefore investigated the clinical and radiographic outcome after posterior bisegmental instrumentation and monosegmental anterior spondylodesis using an autologous rib graft for unstable thoracolumbar burst fractures.

PATIENTS AND METHODS

This was a retrospective analysis of 32 consecutive patients at a single center. The monosegmental Cobb angle was measured preoperatively, postoperatively, then 6 and 12 months postoperatively, and also after implant removal. Anterior vertebral fusion was graded on conventional radiographs according to the criteria proposed by Molinari.

RESULTS

Segmental kyphosis at the fracture site was corrected from a median of -20° (95% CI: -21.2 to -18.8) to -1.0° (95% CI: -2.7 to 0.7) postoperatively. 1 year after surgery, the segmental angle had decreased by a median of 2.0° (95% CI: 0.2 to 2.8). The spondylodesis fused in all patients, which was evident from incorporation and remodeling of the rib grafts. The median correction loss after implant removal was 0.0° (95% CI: -0.5 to 0.5). 26 of the 32 patients reported having no back complaints at the last follow-up (2 years postoperatively). 1 patient suffered from intercostal neuralgia, and 5 patients reported mild to moderate back pain.

INTERPRETATION

Short-segment posterior instrumentation and anterior spondylodesis using an autologous rib graft resulted in sufficient correction of posttraumatic segmental kyphosis. There was no clinically relevant correction loss, and the majority of patients had no back complaints at the 2-year follow-up.

Salmonella prostatitis in a man with spinal cord injury

CONTEXT

Prostatitis is a very unusual manifestation of Salmonella urinary tract infection and has not been reported in men with spinal cord injury (SCI).

FINDINGS

A 57-year-old man with paraplegia and a history of recurrent symptomatic urinary tract infections presented with Salmonella typhimurium prostatitis. Clinical and sonographic examination of the urinary tract, as well as urinalysis including microbiologic examination, revealed no relevant abnormalities. The microbiologic analysis of the ejaculate revealed growth of monophasic Salmonella enterica ssp. enterica serotype 4,12:i:-. A 6-week course of antibiotic treatment was initiated. There were no recurrent symptomatic urinary tract infections during follow-up.

CONCLUSION

Salmonellosis is a reportable disease and carriers have to refrain from activities in the food sector. Therefore, Salmonella prostatitis should be considered and excluded in men with SCI and a history of recurrent urinary tract infection who use intermittent catheterization for bladder management.

Urodynamic results, clinical efficacy, and complication rates of sacral intradural deafferentation and sacral anterior root stimulation in patients with neurogenic lower urinary tract dysfunction resulting from complete spinal cord injury

AIMS

To investigate the outcome and complications of sacral deafferentation (SDAF) and sacral anterior root stimulation (SARS) in patients with neurogenic lower urinary tract dysfunction (NLUTD) resulting from complete spinal cord injury (SCI).

METHODS

Retrospective chart analysis of 137 patients who underwent SDAF/SARS at a single institution. Patients were categorized as being at risk of renal damage when the maximum detrusor pressure was >40 cmH2 O or detrusor compliance was <20 ml/cmH2 O.

RESULTS

After a mean follow-up time of 14.8 ± 5.3 years, SDAF/SARS treatment significantly (P < 0.001) reduced the number of patients suffering from elevated detrusor pressure from 65 to 2, and from low detrusor compliance from 62 to 13, respectively. Mean bladder capacity significantly (P < 0.001) improved from 272.4 ± 143.0 to 475.0 ± 82.7 ml. The mean number of symptomatic UTI also decreased significantly (P < 0.001) from 6.2 ± 4.5 to 2.5 ± 2.6 per year. The number of patients suffering from incontinence had significantly (P < 0.001) decreased from 70 to 44. At the last follow-up visit, 107 (78.1%) patients were still using the stimulator. A total of 84 complications requiring surgical revision were observed. Defects of the stimulator cables or the receiver plate were the most common events (n = 38). The retrospective design pertains to the limitations of the study.

CONCLUSIONS

Sacral deafferentation and SARS are an effective treatment option for refractory NLUTD in patients with complete SCI, despite a substantial long-term complication rate.

The Torg-Pavlov ratio for the prediction of acute spinal cord injury after a minor trauma to the cervical spine

BACKGROUND CONTEXT

Acute cervical spinal cord injury (SCI) has been observed in some patients after a minor trauma to the cervical spine. The discrepancy between the severity of the trauma and the clinical symptoms has been attributed to spinal canal stenosis. However, to date, there is no universally established radiological parameter for identifying critical spinal stenosis in these patients. The spinal canal-to-vertebral body ratio (Torg-Pavlov ratio) has been proposed for assessing developmental spinal canal stenosis. The relevance of the Torg-Pavlov ratio for predicting the occurrence and severity of acute cervical SCI after a minor trauma to the cervical spine has not yet been established.

PURPOSE

To investigate the Torg-Pavlov ratio values of the cervical spine in patients suffering from acute cervical SCI after a minor trauma to the cervical spine and the use of the Torg-Pavlov ratio for identifying patients at risk of cervical SCI and predicting the severity and course of symptoms.

STUDY DESIGN/SETTING

Retrospective radiological study of consecutive patients.

PATIENT SAMPLE

Forty-five patients suffering from acute cervical SCI and 68 patients showing no neurologic symptoms after a minor trauma to the cervical spine.

OUTCOME MEASURES

Midvertebral sagittal cervical spinal canal diameter and the sagittal vertebral body diameter. Calculation of the Torg-Pavlov ratio values.

METHODS

Conventional lateral radiographs of the cervical spine (C3-C7) were analyzed to determine the Torg-Pavlov ratio values. Receiver operating characteristic curves were calculated for evaluating the classification accuracy of the Torg-Pavlov ratio for predicting SCI.

RESULTS

The Torg-Pavlov ratio values in the SCI group were significantly (p<.04) smaller compared with that in the control group. A Torg-Pavlov ratio cutoff value of 0.7 yielded the greatest positive likelihood ratio for predicting the occurrence of SCI. However, there were no significant differences in the Torg-Pavlov ratio values between the different American Spinal Injury Association Impairment Score groups and between patients with complete, partial, and no recovery of symptoms.

CONCLUSIONS

Developmental cervical spinal canal stenosis assessed by the Torg-Pavlov ratio was characteristic for patients suffering from acute cervical SCI after a minor trauma to the cervical spine. Patients at risk of SCI after a minor trauma to the cervical spine can be identified by applying a Torg-Pavlov ratio cutoff value of 0.7. Other factors in addition to the spinal canal-to-vertebral body ratio affect the severity and course of symptoms as a result of cervical SCI.

Release of ANP and fat oxidation in overweight persons during aerobic exercise in water

Exercise in water compared to land-based exercise (LE) results in a higher release of natriuretic peptides, which are involved in the regulation of exercise-induced adipose tissue lipolysis. The present study was performed to compare the release of atrial natriuretic peptide (ANP) and free fatty acids (FFA) during prolonged aerobic water-based exercise (WE) with the release after an identical LE. 14 untrained overweight subjects performed 2 steady state workload tests on the same ergometer in water and on land. Before and after exercise, venous blood samples were collected for measuring ANP, FFA, epinephrine, norepinephrine, insulin and glucose. The respiratory exchange ratio (RER) was determined for fat oxidation.The exercises resulted in a significant increase in ANP in LE (61%) and in WE (177%), and FFA increased about 3-fold in LE and WE with no significant difference between the groups. Epinephrine increased, while insulin decreased similarly in both groups. The RER values decreased during the exercises, but there was no significant difference between LE and WE. In conclusion, the higher ANP concentrations in WE had no additional effect on lipid mobilization, FFA release and fat oxidation. Moderate-intensity exercises in water offer no benefit regarding adipose tissue lipolysis in comparison to LE.

Effects of solifenacin in patients with neurogenic detrusor overactivity as a result of spinal cord lesion

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

To investigate the urodynamic effects of solifenacin treatment for neurogenic detrusor overactivity (NDO) in patients with spinal cord injury (SCI).

SETTING

Paraplegic center in Switzerland.

METHODS

Retrospective analysis of case histories and urodynamic data of 35 SCI patients receiving solifenacin for treatment of NDO between 2008 and 2012. Patients were categorized as being at risk of renal damage when maximum detrusor pressure was >40 cm H2O or detrusor compliance was <20 ml cm(-1) H2O.

RESULTS

Solifenacin treatment was initiated 7.3 years after SCI. Most patients (63%) had already been taking other antimuscarinic drugs. After 13.1 months (median, interquartile range 6.1-19.5 months), solifenacin treatment had resulted in significant (P<0.03) improvements in bladder capacity (median +30.0 ml), maximum detrusor pressure (median -7.0 cm H2O), reflex volume (median +62.5 ml) and detrusor compliance (median +25.0 ml cm(-1) H2O). Furthermore, fewer patients presented with a risk of renal damage. However, this difference was not significant (P>0.1). The number of patients suffering from incontinence had not changed significantly. Eight and two patients discontinued solifenacin treatment as a result of insufficient efficacy and intolerable adverse events, respectively. One patient had discontinued solifenacin treatment without further explanation.

CONCLUSION

Solifenacin treatment significantly improved bladder capacity, detrusor compliance, reflex volume and maximum detrusor pressure. Solifenacin treatment seems to be an effective oral treatment of NDO after SCI.

120 THE DEVELOPMENTAL COMPETENCE OF TADPOLES PRODUCED IN VITRO FROM THE ENDANGERED DUSKY GOPHER FROG (RANA SEVOSA) USING EXOGENOUS HORMONE TREATMENT

Dusky gopher frogs once existed throughout the states of Mississippi, Alabama and Louisiana. Presently, the USA Fish and Wildlife Service estimates that there are less than 100 frogs left in the wild, with almost all of these residing in a single pond in Mississippi, making the dusky gopher frog America's most endangered frog species. Their habitat has been threatened by residential and forestry development, as well as from fire suppression and the decline of gopher tortoises, whose burrows the frogs use for shelter. The USA Fish and Wildlife Service brought the first dusky gopher frogs into captivity in 2001 and they have been kept at the Memphis Zoo since 2003 and at Omaha's Henry Doorly Zoo since 2004. Natural breeding attempts in captivity have been unsuccessful despite efforts to artificially mimic what is known to be the appropriate seasonal environmental (e.g. light, humidity, temperature) and social cues (e.g. calls from wild frogs during the breeding season) that stimulate reproduction in situ. Also, there was a concern about the incidences of abnormalities (e.g. spindly legs) from inadequate husbandry conditions (e.g. nutritional deficiencies) or diseases in tadpoles and froglets produced ex situ (e.g. dermomycoides). The objectives of this study were (1) to examine the developmental competence of tadpoles produced by exogenous hormone treatment for IVF to complete normal metamorphosis into viable froglets ex situ and (2) to determine the incidence of developmental abnormalities or dermomycoides in the froglets produced ex situ. Males and females were first separated by the identification of black male nuptial pads used during amplexus. Males and females were stimulated to spermiate and ovulate, respectively, using a variation of a standard amphibian hormonal stimulation protocol (Kouba et al. 2012 Reprod. Fertil. Dev. 24). As a result, more than 1460 viable tadpoles (61% of fertilized eggs) were produced from 18 segregated genetic pairings. To date, 602 (41%) of the tadpoles have completed normal metamorphosis into viable froglets (over 6 times the known existing population in situ), 51% were either culled to examine for dermomycoides or died for a variety of known (accidental) and unknown reasons (abnormal appendage development accounting for less than 7%) and 8% have yet to metamorphose after 9 months. The incidence of dermomycoides in the culled individuals was 100%; however, a study being conducted concurrently in their native habitat has confirmed that the organism does exist in situ with the dusky gopher frogs, which act as natural carriers. Efforts are currently in place to establish reintroduction programs for the dusky gopher froglets produced ex situ to increase the dwindling wild population now that tadpoles produced by IVF have been shown to be developmentally competent. In conclusion, IVF can be used to produce tadpoles of the dusky gopher frog with a low incidence of abnormalities, but the tadpoles were found to be carriers of the organism dermomycoides similar to their counterparts in the wild.

116 DEVELOPMENT OF ASSISTED REPRODUCTION TECHNOLOGIES FOR THE ENDANGERED MISSISSIPPI GOPHER FROG (RANA SEVOSA) AND SPERM TRANSFER FOR IN VITRO FERTILIZATION

Species-specific differences in breeding strategies and physiology have limited the application of assisted reproductive technologies (ART) for critically endangered amphibians in captive assurance colonies. In 2006, the Memphis Zoo (MZ) initiated a program to develop ART for the critically endangered Mississippi gopher frog after natural breeding failed. Standard gamete collection and IVF developed by MZ for reproducing endangered toads such as the Wyoming or boreal toad were applied to the gopher frog with little success, especially hormonal therapy for sperm production. Using the leopard frog as a model species for Ranids, we tested the time and dose dependence of a luteinizing hormone releasing hormone analogue (LHRHa) and hCG on sperm quantity and quality. Initial findings from the leopard frog study were critical in designing the study on gopher frogs. Our objectives were to (1) compare 2 different hormones administered intraperitoneal (500 IU hCG vs 15 μg LHRHa) or their combination on spermiation in gopher frogs; (2) develop in vivo oocyte maturation and ovulation protocols using LHRHa (15 μg) and hCG (500 IU); and (3) transfer this technology to another institution as proof of principle. In gopher frogs, 100 and 83% of the males produced sperm in response to the LHRHa and the combination treatment, respectively, whereas only 16% responded to hCG alone. Sperm concentration peaked at 1 h post-administration for all treatments, with the LHRH/hCG cocktail treatment producing the highest concentration of sperm (mean = 4.6 × 106 ± 1.2 × 106 sperm mL–1, n = 6). No differences in motility were observed between treatments (P > 0.05). For females, a series of priming hormones of hCG and LHRHa were given several months before an ovulatory hormone regimen resulting in ovulation by 100% of the females (n = 6), whereas animals not primed failed to ovulate (n = 4). These 3 separate priming and IVF trials conducted between 2008 and 2010 resulted in each female laying ∼2000 eggs, with an average fertilization rate of 76% for inseminated eggs and hundreds of tadpoles produced. These IVF tadpoles represent the first captive reproduction of gopher frogs and highlight how ART can be applied to conservation and genetic management of threatened species. Subsequently, we tested our IVF protocols on gopher frogs at Omaha's Henry Doorly Zoo using fresh (collected on site) and chilled, shipped sperm from MZ. We collected 6169 eggs from 9 hormone-primed females with all animals ovulating. A portion of the total eggs ovulated were inseminated, resulting in 2401 fertilized eggs (38.9% of total eggs collected) across 18 different male–female pairings leading to viable tadpoles. In addition, sperm transferred overnight from the MZ produced 202/441 fertilized eggs (46%). The transfer of this technology and production of endangered amphibians using chilled, shipped sperm from live animals is a conservation milestone that can be applied to other captive breeding programs.

Effect of vertebral cement augmentation with polymethylmethacrylate on intervertebral disc and bone tissue

Vertebral cement augmentation is reported to be a safe and effective technique for providing stabilization and pain relief. However, adjacent intervertebral discs may be at risk of accelerated degeneration as a result of aggravated nutritional constraints. Therefore, we investigated the effects of injecting polymethylmethacrylate (PMMA) into three adjacent lumbar vertebrae on intervertebral disc and vertebral bone tissue in 12 skeletally mature sheep. After 6 and 12 months of augmentation, the sheep were euthanized and their spines were processes for histological evaluation. Semiquantitative histomorphological analysis of discs and endplates was conducted using published criteria. Histomorphological changes in the augmented bone were assessed qualitatively. Approximately 80% of the length of the endplates was in contact with PMMA. However, there was no significant difference between the histopathological score of the discs adjacent to augmented vertebrae and the score of the control discs. Bone tissue reaction to PMMA was characterized by a thin fibrous tissue layer and occasional foreign-body reactions. New bone formation was present in all augmented vertebrae. Concerns about aggravation of disc degeneration as a result of vertebral cement augmentation seem to be unsubstantiated. Furthermore, adverse effects of PMMA cement on bone biology do not seem to be a relevant issue.

Aerosolized semifluorinated alkanes as excipients are suitable for inhalative drug delivery--a pilot study

Semifluorinated alkanes (SFAs) have been described as potential excipients for pulmonary drug delivery, but proof of their efficacy is still lacking. We tested whether SFA formulations with the test drug ibuprofen can be nebulised and evaluated their pharmacokinetics. Physico-chemical properties of five different ibuprofen formulations were evaluated: an aqueous solution (H2O), two different SFAs (perfluorohexyloctane (F6H8), perfluorobutylpentane (F4H5)) with and without ethanol (SFA/EtOH). Nebulisation was performed with a jet catheter system. Inhalative characteristics were evaluated by laser diffraction. A confirmative animal study with an inhalative single-dose (6 mg/kg) of ibuprofen with each formulation was performed in anaesthetised healthy rabbits. Plasma samples at defined time points and lung tissue harvested after the 6-h study period were analyzed by HPLC-MS/MS. Pharmacokinetics were calculated using a non-compartment model. All formulations were nebulisable. No differences in aerodynamic diameters (MMAD) were detected between SFA and SFA/EtOH. The ibuprofen plasma concentration-time curve (AUC) was highest with F4H5/EtOH. In contrast, F6H8/EtOH had the highest deposition of ibuprofen into lung tissue but the lowest AUC. All tested SFA and SFA/EtOH formulations are suitable for inhalation. F4H5/EtOH formulations might be used for rapid systemic availability of drugs. F6H8/EtOH showed intrapulmonary deposition of the test drug.

Cardiovascular changes after PMMA vertebroplasty in sheep: the effect of bone marrow removal using pulsed jet-lavage

Clinically, the displacement of intravertebral fat into the circulation during vertebroplasty is reported to lead to problems in elderly patients and can represent a serious complication, especially when multiple levels have to be treated. An in vitro study has shown the feasibility of removing intravertebral fat by pulsed jet-lavage prior to vertebroplasty, potentially reducing the embolization of bone marrow fat from the vertebral bodies and alleviating the cardiovascular changes elicited by pulmonary fat embolism. In this in vivo study, percutaneous vertebroplasty using polymethylmethacrylate (PMMA) was performed in three lumbar vertebrae of 11 sheep. In six sheep (lavage group), pulsed jet-lavage was performed prior to injection of PMMA compared to the control group of five sheep receiving only PMMA vertebroplasty. Invasive recording of blood pressures was performed continuously until 60 min after the last injection. Cardiac output and arterial blood gas parameters were measured at selected time points. Post mortem, the injected cement volume was measured using CT and lung biopsies were processed for assessment of intravascular fat. Pulsed jet-lavage was feasible in the in vivo setting. In the control group, the injection of PMMA resulted in pulmonary fat embolism and a sudden and significant increase in mean pulmonary arterial pressure. Pulsed jet-lavage prevented any cardiovascular changes and significantly reduced the severity of bone marrow fat embolization. Even though significantly more cement had been injected into the lavaged vertebral bodies, significantly fewer intravascular fat emboli were identified in the lung tissue. Pulsed jet-lavage prevented the cardiovascular complications after PMMA vertebroplasty in sheep and alleviated the severity of pulmonary fat embolism.

Semifluorinated alkanes--a new class of excipients suitable for pulmonary drug delivery

INTRODUCTION

Semifluorinated alkanes (SFAs) are considered as diblock molecules with fluorocarbon and hydrocarbon segments. Unlike Perfluorocarbons (PFCs), SFAs have the potential to dissolve several lipophilic or water-insoluble substances. This makes them possibly suitable as new excipients for inhalative liquid drug carrier systems.

PURPOSE

The aim of the study was to compare physico-chemical properties of different SFAs and then to test their respective effects in healthy rabbit lungs after nebulisation.

METHODS

Physico-chemical properties of four different SFAs, i.e. Perfluorobutylpentane (F4H5), Perfluorohexylhexane (F6H6), Perfluorohexyloctane (F6H8) and Perfluorohexyldodecane (F6H12) were measured. Based on these results, aerosol characteristics of two potential candidates suitable as excipients for pulmonary drug delivery, i.e. F6H8 and F4H5, were determined by laser light diffraction. Tracheotomised and ventilated New Zealand White rabbits were nebulised with either a high- or a low dose of SFAs (F6H8(low/high) and F4H5(low/high)) or saline (NaCl). Ventilated healthy animals served as controls (Sham). Arterial blood gases, lung mechanics, heart rate and blood pressure were recorded prior to nebulisation and in 30 min intervals during the 6-h study period.

RESULTS

Out of the four SFAs studied initially, no satisfactory behaviour as a solvent has to be expected because of low lipophilicity for F6H6. Output rate during aerosolisation was very low for F6H12. F6H8 and F4H5 presented comparable aerosolisation characteristics and lipophilicity and were therefore tested in the in vivo model. Aerosol therapy, either SFAs or saline, impaired paO2/FiO2 ratio, dynamic lung compliance and respiratory mechanics in all groups, except for F4H5(low) group which behaved like the control group (Sham). F4H5(low) had no adverse effects on gas exchange or pulmonary mechanics.

CONCLUSIONS

Perfluorobutylpentane (F4H5) in a low-dose application may be suitable as a new inhalable excipient in SFA-based pulmonary drug delivery systems for lipophilic or water-insoluble substances.

The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

We propose a fundamental geographic distribution for the wolverine ( Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS classified satellite images representing persistent snow cover from 24 April to 15 May, which encompasses the end of the wolverine’s reproductive denning period. To investigate the wolverine’s spatial relationship with average maximum August temperatures, we used interpolated temperature maps. We then compared and correlated these climatic factors with spatially referenced data on wolverine den sites and telemetry locations from North America and Fennoscandia, and our contemporary understanding of the wolverine’s circumboreal range. All 562 reproductive dens from Fennoscandia and North America occurred at sites with persistent spring snow cover. Ninety-five percent of summer and 86% of winter telemetry locations were concordant with spring snow coverage. Average maximum August temperature was a less effective predictor of wolverine presence, although wolverines preferred summer temperatures lower than those available. Reductions in spring snow cover associated with climatic warming will likely reduce the extent of wolverine habitat, with an associated loss of connectivity.

The effect of pulsed jet lavage in vertebroplasty on injection forces of PMMA bone cement: an animal study

Percutaneous vertebroplasty, comprising of the injection of polymethylmethacrylate (PMMA) into vertebral bodies, is an efficient procedure to stabilize osteoporotic compression fractures as well as other weakening lesions. Besides fat embolism, cement leakage is considered to be one of the major and most severe complications during percutaneous vertebroplasty. The viscosity of the PMMA during injection plays a key role in this context. It was shown in vitro that the best way to lower the risk of cement leakage is to inject the cement at higher viscosity, which is requires high injection forces. Injection forces can be reduced by applying a newly developed lavage technique as it was shown in vitro using human cadaver vertebrae. The purpose of this study was to prove the in vitro results in an in vivo model. The investigation was incorporated in an animal study that was performed to evaluate the cardiovascular reaction on cement augmentation using the lavage technique. Injection forces were measured with instrumentation for 1 cc syringes, additionally acquiring plunger displacement. Averaged injection forces measured, ranged from 12 to 130 N and from 28 to 140 N for the lavage group and the control group, respectively. Normalized injection forces (by viscosity and injection speed) showed a trend to be lower for the lavage group in comparison to the control group (P = 0.073). In conclusion, the clinical relevance on the investigated lavage technique concerning lowering injection forces was only shown by trend in the performed animal study. However, it might well be that the effect is more pronounced for osteoporotic vertebral bodies.

161 CRYOPRESERVATION OF CORN SNAKE, ELAPHE GUTATTA, SEMEN

The purpose of this investigation was to develop a protocol for cryopreserving snake semen using the corn snake, Elaphe gutatta, as the model species. This experiment is part of a five year investigation where the influences of diluents, cryoprotectants, cooling and thawing rates on sperm survival were studied. This report presents one protocol found to be effective for cryopreserving corn snake semen as determined by post-thaw motility parameters in vitro. Semen was collected by applying pressure to the lower abdomen and continuing distally towards the cloaca to remove any feces or urates. The cloaca was washed using PBS, then a more local pressure was applied to each side of the vent to cause the hemipenes to evert and subsequently ejaculate. The semen (approximately 5 μL) was then collected using a sterile transfer pipette, placed in 120 μL Biladyl A containing 20% egg yolk (Minitube, 13502/0501), and analyzed for motility, rate of forward progression (RFP; 0–5), and concentration. The semen was further diluted at room temperature at 1:1 v/v with Biladyl A containing 20% egg yolk and 34% Glycerol (Sigma, G2025), yielding a final concentration of 17% Glycerol. The diluted semen was then loaded into 250-μL straws and slowly cooled for 1 hour. The straws were then placed 1 inch above a liquid nitrogen bath for ten minutes and finally plunged into the nitrogen where it remained frozen. The cryopreserved semen was thawed by placing the straws into a 50°C water bath for 8 s, then emptied into microcentrifuge tubes and the sperm were evaluated for motility and RFP. The mean motility of the fresh samples was 72.5% (66.4–77.7%). The mean post-thaw motility of sperm over six trials was 27.1% (17.8–50.2%). The mean RFP was 0.75 (0.5–1.0). The differences between fresh and post-thawed mean motilities were shown to be significant using a chi-square analysis (P < 0.0001). Density gradient centrifugation (DGC) was applied in one trial where the semen had an initial post-thaw motility of 50.2% with an RFP of 0.5. After the centrifugation treatment, the motility increased to 64.8% with an RFP of 3. The DGC media was composed of 400 μL 45% Percoll (Sigma, P4937) layered over 400 μL 90% Percoll. The density gradients were centrifuged at 700g for 30 min after which time the pellets were washed in 500 μL pre-warmed TL Hepes Solution (Lonza, 04-616F) and centrifuged at 300g for 10 min to remove the Percoll. The resulting sperm pellets were then resuspended in a small volume of the pre-warmed Hepes. Thus far, the protocol using 17% Glycerol in Biladyl A with 20% egg yolk has proven to be the most successful for cryopreserving corn snake semen. The use of DGC enhanced the number of usable sperm leaving sperm of higher motility and RFP possibly due to the absence of seminal plasma or cryoprotective agents that may detrimentally affect sperm quality. There are no known reports of the use of DCG with snake semen. Further studies are underway to improve these results and successfully use cryopreserved snake semen for artificial insemination and cryobanking for the long-term genetic management of endangered snake species.

Initial treatment with fixed-dose combination rosiglitazone/glimepiride in patients with previously untreated type 2 diabetes

AIM

This study assessed the efficacy and safety of two different dosing regimens of fixed-dose combination (FDC) rosiglitazone (RSG) plus glimepiride (GLIM) compared with RSG or GLIM monotherapy in drug-naive subjects with type 2 diabetes mellitus (T2DM).

METHODS

Drug-naive subjects (n = 901) were enrolled into this 28-week, double-blind, parallel-group study if their glycosylated haemoglobin A(1c) (HbA(1c)) was >7.5% but <or=12%. Subjects were randomized to receive either GLIM [4 mg once daily (OD) maximal], RSG (8 mg OD maximal) or RSG/GLIM FDC regimen A (4 mg/4 mg OD maximal) or RSG/GLIM FDC regimen B (8 mg/4 mg OD maximal). Patients were assessed for efficacy and safety every 4 weeks for the first 12 weeks of the study, and at weeks 20 and 28. The primary efficacy endpoint was change in HbA(1c) from baseline. Key secondary endpoints included the proportion of patients achieving recommended HbA(1c) and fasting plasma glucose (FPG) targets; change from baseline in FPG, insulin, C-reactive protein (CRP), adiponectin, free fatty acids and lipids; and percentage change in homeostasis model assessment-estimated insulin sensitivity and beta-cell function. Safety evaluations included adverse-event (AE) monitoring and clinical laboratory evaluations.

RESULTS

At week 28, both RSG/GLIM FDC regimens significantly reduced HbA(1c) (mean +/- s.d.: -2.4 +/- 1.4% FDC regimen A; -2.5 +/- 1.4% FDC regimen B) to a greater extent than RSG (-1.8 +/- 1.5%) or GLIM (-1.7 +/- 1.4%) monotherapy (model-adjusted mean treatment difference, p < 0.0001 vs. both RSG and GLIM). Significantly more subjects achieved HbA(1c) target levels of <or=6.5 and <7% with either RSG/GLIM FDC regimen compared with RSG or GLIM alone (model-adjusted odds ratio, p < 0.0001 for both comparisons). Similarly, a significantly greater reduction in FPG levels was observed in subjects treated with the RSG/GLIM FDC [mean +/- s.d. (mg/dl): -69.5 +/- 57.5 FDC regimen A; -79.9 +/- 56.8 FDC regimen B) compared with RSG (-56.6 +/- 58.1) or GLIM (-42.2 +/- 66.1) monotherapy (model-adjusted mean treatment difference, p < 0.0001 for both comparisons). Improvement in CRP was also observed in subjects who were treated with a RSG/GLIM FDC or RSG monotherapy compared with GLIM monotherapy. RSG/GLIM FDC was generally well tolerated, with no new safety or tolerability issues identified from its monotherapy components, and a similar AE profile was observed across FDC regimens. The most commonly reported AE was hypoglycaemia, and the incidence of confirmed symptomatic hypoglycaemia (3.6-5.5%) was comparable among subjects treated with an RSG/GLIM FDC and GLIM monotherapy.

CONCLUSIONS

Compared with RSG or GLIM monotherapy, the RSG/GLIM FDC improved glycaemic control with no significant increased risk of hypoglycaemia. RSG/GLIM FDC provides an effective and well-tolerated treatment option for drug-naive individuals with T2DM.

Influence of bone marrow fat embolism on coagulation activation in an ovine model of vertebroplasty

BACKGROUND

Intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially serious complication during vertebroplasty. The release of fatty material and thromboplastin from the bone marrow cavity during vertebroplasty may activate the coagulation cascade resulting in thrombogenesis, and pharmacological prophylaxis may therefore prevent cardiovascular complications. Thus, the effects of bone marrow fat embolism on coagulation activation during vertebroplasty were investigated with use of an animal model.

METHODS

Polymethylmethacrylate was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until sixty minutes after the last injection. Cardiac output, arterial and mixed venous blood gas parameters, and coagulation parameters were measured at selected time-points. Postmortem lung biopsy specimens were assessed for the presence of intravascular fat.

RESULTS

Embolization of bone marrow fat resulted in a sudden and dramatic increase in mean pulmonary arterial pressure and a decrease in mean arterial blood pressure. There were no significant changes in any coagulation parameter from before the injection to after the injection. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSIONS

Injection of polymethylmethacrylate into vertebral bodies caused embolization of bone marrow fat with subsequent transient cardiovascular deterioration, but no changes in coagulation parameters were observed. Thromboembolism did not contribute to the observed cardiovascular changes.

SIMAP--structuring the network of protein similarities

Protein sequences are the most important source of evolutionary and functional information for new proteins. In order to facilitate the computationally intensive tasks of sequence analysis, the Similarity Matrix of Proteins (SIMAP) database aims to provide a comprehensive and up-to-date dataset of the pre-calculated sequence similarity matrix and sequence-based features like InterPro domains for all proteins contained in the major public sequence databases. As of September 2007, SIMAP covers ∼17 million proteins and more than 6 million non-redundant sequences and provides a complete annotation based on InterPro 16. Novel features of SIMAP include a new, portlet-based web portal providing multiple, structured views on retrieved proteins and integration of protein clusters and a unique search method for similar domain architectures. Access to SIMAP is freely provided for academic use through the web portal for individuals at http://mips.gsf.de/simap/and through Web Services for programmatic access at http://mips.gsf.de/webservices/services/SimapService2.0?wsdl.

Plasma levels of endothelin-1 after a pulmonary embolism of bone marrow fat

BACKGROUND

During orthopedic surgery, embolization of bone marrow fat can lead to potentially fatal, intra-operative cardiovascular deterioration. Vasoactive mediators may also be released from the bone marrow and contribute to these changes. Increased plasma levels of endothelin-1 (ET-1) have been observed after pulmonary air and thrombo-embolism. The role of ET-1 in the development of acute cardiovascular deterioration as a result of bone marrow fat embolization during vertebroplasty was therefore investigated.

METHODS

Bone cement was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output, arterial and mixed venous blood gas parameters and plasma ET-1 concentrations were measured at selected time points. Post-mortem, lung biopsies were taken for analysis of intravascular fat.

RESULTS

Cement injections resulted in a sudden (within 1 min) and severe increase in pulmonary arterial pressure (>100%). Plasma concentrations of ET-1 started to increase after the second injection, but no significant changes were observed. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSION

Cement injections into vertebral bodies elicited fat embolism resulting in subsequent cardiovascular changes that were characterized by an increase in pulmonary arterial pressure. Cardiovascular complications as a result of bone marrow fat embolism should thus be considered in patients undergoing vertebroplasty. No significant changes in ET-1 plasma values were observed. Thus, ET-1 did not contribute to the acute cardiovascular changes after fat embolism.

Cardiovascular changes after pulmonary cement embolism: an experimental study in sheep

BACKGROUND AND PURPOSE

Most cement leaks during vertebroplasty are asymptomatic, but pulmonary cement embolism has been reported to cause cardiovascular disturbances and even death. Adding hydroxyapatite (HA) to polymethylmethacrylate (PMMA) cement to reduce the quantity of barium may aggravate cardiovascular deterioration in the event of cement embolism by activating coagulation. Thus, we investigated the cardiovascular changes after pulmonary cement embolism of PMMA with and without HA.

MATERIALS AND METHODS

In 13 sheep, cement (2.0 mL) was injected into the pulmonary trunk. Two different cements were used: 1) standard PMMA and 2) PMMA with 10% HA (PMMA & HA). Arterial, central venous and pulmonary arterial pressures, heart rate, and cardiac output were monitored continuously until 60 minutes after the injection. Blood gases and coagulation parameters (antithrombin, D-dimer) were measured before and after injection.

RESULTS

Mean pulmonary arterial pressure had increased by approximately 9% (PMMA) and 14% (PMMA & HA) 1 minute after injection and stayed elevated. There were no significant differences between the groups. No evidence of thromboembolism was detected.

CONCLUSION

Cement embolism did not result in clinically significant pulmonary arterial hypertension. Adding HA to PMMA cement did not cause more severe cardiovascular changes.

Sildenafil Prevents Cardiovascular Changes after Bone Marrow Fat Embolization in Sheep

Background:

Sudden, intraoperative cardiovascular deterioration as a result of pulmonary embolization of bone marrow fat is a potentially fatal complication during total hip and knee arthroplasty, intramedullary nailing, and spine surgery. Anesthetic management is challenging in the presence of increased right ventricular afterload due to pulmonary hypertension. Selective pulmonary vasodilation may be an appropriate prophylactic or therapeutic measure. The effect of sildenafil (phosphodiesterase inhibitor) on cardiovascular deterioration after bone marrow fat embolization was therefore investigated.

Methods:

Bone cement (polymethylmethacrylate) was injected into three lumbar vertebrae in 12 sheep. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output and arterial and mixed venous blood gas variables were measured at selected time points. Before the first cement injection, 6 animals received a bolus injection (0.7 mg/kg) of sildenafil, with continuous infusion (0.2 mg · kg−1 · h−1) thereafter. Postmortem lung and kidney biopsies were taken for semiquantitative analysis of intravascular fat.

Results:

Fat embolism was associated with a transient increase (21 ± 7mmHg) in pulmonary arterial pressure. A transient decrease in arterial blood pressure and temporary increases in central venous pressure and dead space were also observed. No significant changes in any cardiovascular variable were observed after fat embolism in the sildenafil group. There was significantly (P &lt; 0.05) less intravascular fat in the lungs of the sildenafil (median count of 5 emboli per microscopic view) compared with the control group (median count of 1).

Conclusions:

Administration of sildenafil prevented the acute cardiovascular complications after bone marrow fat embolism in sheep.

Cardiovascular changes after pulmonary embolism from injecting calcium phosphate cement

Concerns have been raised that the use of calcium phosphate (CaP) cements for the augmentation of fractured, osteoporotic bones may aggravate cardiovascular deterioration in the event of pulmonary cement embolism by stimulating coagulation. The aim of the present study was therefore to investigate the cardiovascular changes after pulmonary embolism of CaP cement using an animal model. In 14 sheep, 2.0 mL CaP or polymethylmethacrylate cement were injected intravenously. Cardiovascular parameters and antithrombin levels were monitored until 60 min postinjection. Postmortem, lungs were subjected to CT scanning, and 3D reconstruction of the cement was performed. Intravenous injection of CaP cement resulted in a more severe increase in pulmonary arterial pressure and decrease in arterial blood pressure. Disintegration of the CaP cement seemed to be the reason for the more severe reaction. There was no evidence of thromboembolism. Disintegration of CaP cement in circulating blood does not only compromise the mechanical properties, but also represents a risk of cardiovascular complications. Reliable cohesion of CaP cements in an aqueous environment is essential for clinical applications such as osteoporotic bone augmentation.

247 SUCCESSFUL ARTIFICIAL INSEMINATION IN THE CORN SNAKE (ELAPHE GUTATTA), USING FRESH AND COOLED SEMEN

The purpose of this investigation was to develop a non-invasive technique to artificially inseminate snakes using the corn snake, Elaphe gutatta, as the model representative for this taxon. Semen was collected by first applying pressure to the lower abdomen in a continuous distal motion toward the cloaca to remove any feces or urates. The cloaca was then gently washed using phosphate-buffered saline, and a more localized pressure was applied to each side of the vent to evert the hemipenes and, subsequently, the ejaculate. The semen was collected using a sterile transfer pipette and placed into 70 to 90 �L of medium (TL-HEPES solution; Cambrex Bio Science, Inc., Baltimore, MD, USA04–616F) in a sterile microcentrifuge tube, and then analyzed for overall motility, rate of forward progression (RFP, 0–5), and concentration. Based on a previously reported procedure, 10 females were inseminated with either fresh (n = 5) or cooled semen (n = 5; refrigerated for 3 days) one week after recovering from a hibernation period required to stimulate reproduction in this species. The overall sperm motility and concentration for females inseminated with fresh or cooled semen was 92%, 9.6 million sperm mL-1; and 85%, 6.1 million sperm mL-1, respectively. Immediately prior to insemination, the same method for expressing feces and urates in the males was applied to the females. The insemination dose (50 �L semen per oviduct) was drawn into a 1-mL latex- and silicone-free tuberculin syringe (Norm-Ject; VWR, Batavia, IL, USA) that was connected to a feeding/dosing needle (EJAY International, Issaquah, WA, USA) with a ball tip to prevent any potential damage during the insemination. The tip of the needle was then moved around the inner tissue of the vent to relax the cloaca, and the insertion continued until resistance was found indicating the vicinity of the oviducts. The extended semen was carefully deposited on both sides, and then the needle was slowly withdrawn. The offspring were tested for parentage to verify the success of the insemination. Blood was collected from the dorsal aorta posterior to the cloaca and stored in 10 mM Tris at 4�C. The DNA was extracted using a phenyl : chloroform : isoamyl alcohol (PCI) extraction method. Eight microsatellite loci were used for the paternity exclusion analysis: Eob�1, Eob�3, Eob�10, Eob�13, Eob�16, Eob�34, Eob�366, and Eob�373 (IDT, Coraville, IA, USA). All males and females in the collection were tested, and parental candidates were excluded if 2 or more allele mismatches occurred. From the total number of females inseminated, 3 females laid 51 eggs. Two females inseminated with cooled semen laid 36 eggs, of which 5 eggs were hatched, and the remaining were either unfertilized (n = 25) or non-viable (n = 6). All 5 hatched eggs were laid by one of the females. The third female inseminated with fresh semen laid 15 eggs, resulting in 5 hatching and 10 unfertilized eggs. The parentage test validated the AI a success as the alleles correlated between the adults and the offspring. In conclusion, artificial insemination was successful using both freshly collected and cooled (3 days) semen. Further studies are underway to improve the success rate in order to maximize the efficiency of this technology, and thus assist in the genetic preservation of endangered snake species.

Abnormal glucose metabolism and features of the metabolic syndrome are common in patients presenting for elective cardiac catheterization

BACKGROUND

Abnormalities of glucose metabolism and the metabolic syndrome, including excess bodyweight, are potentially modifiable risk factors for cardiac morbidity and mortality. This study aimed to determine the prevalence of these in a group of patients presenting for elective cardiac catheterization or percutaneous intervention.

METHODS

Data were prospectively collected on 297 consecutive patients presenting for elective cardiac catheterization or percutaneous intervention at a single tertiary referral centre. Demographic data, risk factors, medications and coronary angiogram results were recorded. Fasting lipids, fasting glucose, HbA1c levels were measured and if necessary an oral glucose tolerance test was carried out. Logistic regression and contingency table analysis examined associations of these with ethnicity.

RESULTS

Impaired glucose metabolism (diabetes, impaired glucose tolerance or impaired fasting glucose) was present in 46.1% with our screening programme detecting previously unknown impaired glucose metabolism in 22.9%. Impaired glucose metabolism was strongly associated with non-European ethnicity (P < 0.0001). The metabolic syndrome was present in 49.2%. When defined by ethnic specific cut-offs, overweight or obesity was present in >80% of patients in all ethnic groups.

CONCLUSION

There is a very high prevalence of impaired glucose metabolism and the metabolic syndrome in patients presenting for cardiac catheterization. Impaired glucose metabolism is particularly prevalent in the Polynesian and the Indian and the Sri Lankan ethnic groups. Screening of patients undergoing elective cardiac catheterization identifies a significant number of patients with undiagnosed impaired glucose metabolism and should be carried out routinely.

Nuclear translocation of the calcium-binding protein ALG-2 induced by the RNA-binding protein RBM22

By yeast two-hybrid screening using the calcium-binding protein ALG-2 as bait a new target of ALG-2 was identified, the RNA-binding protein RBM22. In order to confirm these interactions in vivo we prepared fluorescent constructs by using the monomeric red fluorescent protein to label ALG-2 and the enhanced green fluorescent protein to label RBM22. Confocal microscopy of NIH 3T3 cells transfected with either ALG-2 or RBM22 expression constructs encoding fluorescent fusion proteins alone revealed that the majority of ALG-2 was localized in the cytoplasm whereas RBM22 was located in the nucleus. When cells were co-transfected with expression vectors encoding both fusion proteins ALG-2 was found in the nucleus indicating that RBM22 which can shuttle between the cytoplasm and the nucleus may play a role in nuclear translocation of ALG-2. Using zebrafish as a model mRNA homologues of ALG-2 and RBM22 were microinjected into the blastodisc-yolk margin of zebrafish embryos at the 1-cell stage followed by monitoring the fusion proteins during development of the zebrafish. Hereby, we observed that ALG-2 alone evenly distributed within the cell, whereas in the presence of RBM22 the two proteins co-localized within the nucleus. More than 95% of the two proteins co-localized within the same area in the nucleus suggesting a functional interaction between the Ca(2+)-signaling protein ALG-2 and the RNA-binding protein RBM22.

Vertebroplasty and kyphoplasty: a systematic review of 69 clinical studies

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To evaluate the safety and efficacy of vertebroplasty and kyphoplasty using the data presented in published clinical studies, with respect to patient pain relief, restoration of mobility and vertebral body height, complication rate, and incidence of new adjacent vertebral fractures.

SUMMARY OF BACKGROUND DATA

Vertebroplasty and kyphoplasty have been gaining popularity for treating vertebral fractures. Current reviews provide an overview of the procedures but are not comprehensive and tend to rely heavily on personal experience. This article aimed to compile all available data and evaluate the clinical outcome of the 2 procedures.

METHODS

This is a systematic review of all the available data presented in peer-reviewed published clinical trials. The methodological quality of included studies was evaluated, and data were collected targeting specific standard measurements. Where possible, a quantitative aggregation of the data was performed.

RESULTS

A large proportion of subjects had some pain relief, including 87% with vertebroplasty and 92% with kyphoplasty. Vertebral height restoration was possible using kyphoplasty (average 6.6 degrees ) and for a subset of patients using vertebroplasty (average 6.6 degrees ). Cement leaks occurred for 41% and 9% of treated vertebrae for vertebroplasty and kyphoplasty, respectively. New fractures of adjacent vertebrae occurred for both procedures at rates that are higher than the general osteoporotic population but approximately equivalent to the general osteoporotic population that had a previous vertebral fracture.

CONCLUSIONS

The problem with stating definitely that vertebroplasty and kyphoplasty are safe and effective procedures is the lack of comparative, blinded, randomized clinical trials. Standardized evaluative methods should be adopted.

In vivo temperature profile of intervertebral discs and vertebral endplates during vertebroplasty: an experimental study in sheep

STUDY DESIGN

Experimental study of temperature profiles during vertebroplasty.

OBJECTIVES

To define accurate temperature profiles during vertebroplasty in an in vivo animal model.

SUMMARY OF BACKGROUND DATA

Controversy still exists whether vertebroplasty achieves its analgesic effect by stabilizing fracture fragments or due to thermal damage of sensory nerves inside the vertebral body. Furthermore, the energy release during cement polymerization may cause thermal injury to the spinal cord or intervertebral discs.

METHODS

A total of 4.0 mL PMMA was injected into three lumbar vertebrae of four skeletally mature mixed-bred ewes. Nine separate K-type thermocouples were placed into 12 vertebrae and their adjacent intervertebral discs. Temperature changes were recorded continuously before, during, and after the injection.

RESULTS

The highest peak temperatures were measured at the cranial endplate (mean 42.4 +/- 8.8 C) and in the center of the vertebral body (mean 43.3 +/- 6.9 C). Temperatures stayed above 40 C for approximately 2.5 minutes. Peak temperatures in the discs and at the dorsal wall (closest to spinal cord) did not exceed 41 C and 47 C and stayed above 40 C for approximately 1.5 minutes.

CONCLUSIONS

The intervertebral discs and the spinal cord do not seem to be in danger of thermal damage during vertebroplasty. The measured energy does not seem to be sufficient for the palliative effect achieved by vertebroplasty.

Polymethylmethacrylate causes prolonged pulmonary hypertension during fat embolism: a study in sheep

BACKGROUND

Fat embolism (FE), the release of bone marrow contents into the circulation and the subsequent cardiovascular changes, is still a potentially fatal com-plication during orthopedic surgery. Different causative factors have been suggested, but the exact pathomechanism of FE still remains unclear. We investigated the role of polymethylmethacrylate (PMMA) in FE during vertebroplasty in sheep.

METHODS

In 8 sheep, two vertebral bodies were augmented alternatively with PMMA or bone wax. Pulmonary and cardiovascular parameters were monitored during the procedure.

RESULTS

The peak response was similar for both groups and characterized by hypotension, a drop in cardiac output and pulmonary hypertension. However, the recovery in pulmonary arterial pressure and pulmonary vascular resistance was quicker in the wax group.

INTERPRETATION

The injection of PMMA may cause prolonged pulmonary hypertension during vertebro-plasty and also arthroplasty. Surgeons should be aware of this potential cardiovascular complication, especially in patients with impaired pulmonary and cardiovascular function.

Clinical measurements of cement injection pressure during vertebroplasty

STUDY DESIGN

Clinical study of injection pressure during vertebroplasty.

OBJECTIVES

To investigate the range of injection pressures during conventional vertebroplasty interventions and to study the influence of syringe design and cement polymerization time on injection pressure.

SUMMARY OF BACKGROUND DATA

Vertebroplasty is an efficient procedure for the treatment of painful vertebral fractures. However, cement leakage is a potentially serious complication. Although injection pressure has been suggested as a factor for extravasation risk, to date, there are only anecdotal reports of pressure data for cement augmentation in the clinic.

METHODS

Using a syringe holder instrumented with load and displacement transducers, injection pressure and volume were recorded in vivo during conventional cement augmentation. Wide (3 mm opening) and normal (1.8 mm opening) syringes were alternated such that each type was evaluated for early (300-500 seconds postmixing) and late (>500 seconds postmixing) cement polymerization time. The influence of syringe type and polymerization time on injection pressure was evaluated using a multifactorial analysis of variance followed by Scheffe post hoc comparison.

RESULTS

The maximum peak injection pressure measured was 3215 kPa. The average pressure peaks for normal and wide syringes were 1693 +/- 653 kPa and 1727 +/- 597 kPa, respectively. No statistically significant differences were found between injection pressures with wide and normal syringes. Higher injection pressures were observed later in the polymerization process.

CONCLUSIONS

High injection pressures approaching 20 atmospheres are reached during conventional vertebroplasty. Widening the syringe tip diameter did not significantly change injection pressures, whereas elapsed time did. Further research is needed to improve injection equipment and materials for vertebroplasty.

Progression of radiolucent lines in cementless twin-bearing low-contact-stress knee prostheses: a retrospective study

A total of 134 low-contact-stress (LCS) total knee arthroplasties (TKAs) with mobile meniscal bearings were implanted in 121 patients with a mean age of 74 years (range, 49-91 years) at the time of surgery. The radiographic results obtained from 91 prostheses at an average follow-up of 7.5 years (range, 4.8-9.6 years) showed that radiolucent lines (RLL) appeared most frequently near the tibial plateau (97%) and that most RLL were present immediately postoperatively (67%) or appeared within the first year (96%). RLL were predominantly nonprogressive (99%). Progressive RLL did not affect the fixation or stability of the prosthesis. There were no revisions for aseptic loosening. Cementless LCS TKA achieves excellent radiologic and clinical midterm results.

In vivo comparison of the osseointegration of vacuum plasma sprayed titanium- and hydroxyapatite-coated implants

For the last 15 years, orthopedic implants have been coated with hydroxyapatite (HA) to improve implant fixation. The osteoconductive effect of HA coatings has been demonstrated in experimental and clinical studies. However, there are ongoing developments to improve the quality of HA coatings. The objective of this study was to investigate whether a rough and highly crystalline HA coating applied by vacuum plasma spraying (VPS) had a positive effect on the osseointegration of special, high-grade titanium (Ti) implants with the same surface roughness. Ti alloy implants were coated (VPS) with special, high-grade Ti or HA. The osseointegration of the implants was evaluated by either light microscopy or pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 18 sheep. The interface shear strength increased significantly over all time intervals. By 4 weeks, values had reached approximately 10N/mm(2). However, the difference between the coatings was not significant at any time interval. Direct bone-implant contact was significantly different between the coatings after 2 and 4 weeks, and reached 46% for Ti and 68% for HA implants by 4 weeks. This study indicates that the use of a rough and highly crystalline HA coating, applied by VPS, enhances early osseointegration. Accelerated establishment of secondary implant fixation decreases the risk of early loosening.

Pressurization of vertebral bodies during vertebroplasty causes cardiovascular complications: an experimental study in sheep

STUDY DESIGN

An experimental study of cardiovascular complications arising during vertebroplasty (VP) of multiple levels in sheep.

OBJECTIVES

To investigate the effect of pressurizing vertebral bodies during VP using different materials in the development of fat embolism (FE) and any associated cardiovascular changes.

SUMMARY OF BACKGROUND DATA

Polymethylmethacrylate (PMMA) is the material of choice for VP. However, PMMA has several disadvantages, such as toxicity, exothermic curing, uncertain long-term biomechanical effects, and biocompatibility. Alternative materials are being developed for VP; however, there is the concern that an increase in intraosseous pressure and displacement of bone marrow contents could lead to FE and hypotension during VP regardless of what type of materials is used.

METHODS

In 20 sheep, four vertebral bodies were augmented either with PMMA or bone wax. Heart rate; arterial, central venous, and pulmonary artery pressure; cardiac output; and blood gas values were recorded. Postmortem the lungs were subjected to histologic evaluation.

RESULTS

The consecutive augmentation of four vertebral bodies with PMMA induced a cumulative FE that gradually deteriorated baseline mean arterial blood pressure (MABP) and blood gas values. The augmentation with bone wax resulted in similar cardiovascular changes and amount of intravascular fat in the lungs.

CONCLUSION

There are potential cardiovascular complications during VP of multiple levels regardless of the augmentation material used. The deteriorating baseline MABP during VP is associated with the pressurization of the vertebral bodies rather than with the use of polymethylmethacrylate.

Cardiovascular changes during multiple vertebroplasty with and without vent-hole: an experimental study in sheep

STUDY DESIGN

An experimental study of cardiovascular complications arising during vertebroplasty (VP) of multiple levels.

OBJECTIVES

To investigate the cardiovascular changes during multiple VP and whether a vent-hole has a preventive effect.

SUMMARY OF BACKGROUND DATA

An experimental study and clinical reports showed that fat embolism (FE) and acute hypotension occur during VP. There is the concern that these complications may worsen during VP of multiple levels. Vent-holes may prevent FE during VP.

METHODS

In twenty-two sheep, four vertebral bodies were augmented with polymethylmethacrylate (PMMA). In ten sheep, a vent-hole was drilled into the pedicle contralateral to the injection site. Heart rate, arterial, central venous and pulmonary artery pressure, cardiac output and blood gas values were recorded. The lungs were subjected to histologic evaluation at postmortem.

RESULTS

The consecutive augmentation of four vertebral bodies with PMMA induced a cumulative FE that gradually deteriorated baseline mean arterial blood pressure (MABP) and blood gas values. The deterioration of MABP and change in blood gas values were attenuated, when a vent-hole was drilled. The amount of intravascular fat in the lungs after multiple VP (19%) was reduced when a vent-hole was drilled (9%).

CONCLUSION

Surgeons should be aware of the potential cardiovascular complications during VP of multiple levels. In the clinical setting, a needle in the contralateral pedicle could be used to decompress the vertebral body during the injection of bone cement.

Degradation of hydroxyapatite coating on a well-functioning femoral component

We carried out a histological study of a proximally hydroxyapatite (HA)-coated femoral component, retrieved after 9.5 years of good function. The HA coating had completely degraded. Bone was in direct contact with the titanium surface in all the areas which had been coated, with no interposing fibrous tissue. There were no signs of particles, third-body wear, adverse tissue reactions or osteolysis. Bone remodelling was evident by the presence of resorption lacunae; tetracycline labelling showed bone laid down six years after implantation. The loss of the HA-coating had no negative effect on the osseo-integration of the stem. We conclude that the HA coating contributes to the fixation of the implant and that its degradation does not adversely affect the long-term fixation.

Fat embolism and acute hypotension during vertebroplasty: an experimental study in sheep

STUDY DESIGN

An experimental study of cardiovascular complications that arise during vertebroplasty was conducted.

OBJECTIVE

To investigate the sequential occurrence of fat embolism and hypotension during vertebroplasty.

SUMMARY OF BACKGROUND DATA

Vertebroplasty, the augmentation of vertebrae with polymethylmethacrylate, is a technique for treating osteoporotic compression fractures and achieving prophylactic stabilization of osteoporotic vertebral bodies at risk of fracture. However, there is concern that fat embolism and acute hypotension could occur as in a variety of other orthopedic procedures.

METHODS

In six sheep, 6 mL of polymethylmethacrylate was injected unilaterally into L1. Transesophageal echocardiography monitored the pulmonary artery for echodense particles. Heart rate, arterial and venous pressures, and blood gas values were recorded before and for 25 minutes after injection. The lungs were subjected to postmortem histologic evaluation and compared with lung specimens from two sheep that had not undergone vertebroplasty.

RESULTS

Injection of cement elicited a very rapid decrease in heart rate (within 2 +/- 1 seconds) and a rapid increase in venous pressure (within 3 +/- 1 seconds), which was followed by a fall in arterial pressure (within 5 +/- 2 seconds) (phase 1). Thereafter, showers of echogenic material appeared (within 6 +/- 1 seconds) and lasted for 138 +/- 36 seconds. A second more severe fall in arterial pressure was observed beginning at 18 +/- 2 seconds (phase 2). The injection resulted in an increase in partial pressure of carbon dioxide and a decrease in pH. The histology showed intravascular fat globules and bone marrow cells in lung tissue.

CONCLUSIONS

The results suggest that immediately after cement injection, there was a reflex fall in heart rate and arterial pressure. The second fall in arterial pressure was a consequence of fat emboli passing through the heart and getting trapped in the lungs.

Comparative genomic hybridization analysis in adult T-cell leukemia/lymphoma: correlation with clinical course

Sixty-four patients with adult T-cell leukemia/lymphoma (ATL; 18 patients with indolent subtype and 46 with aggressive subtype) associated with human T-lymphotropic virus type 1 (HTLV-1) were analyzed using comparative genomic hybridization (CGH). The most frequent observations were gains at chromosomes 14q, 7q, and 3p and losses at chromosomes 6q and 13q. Chromosome imbalances, losses, and gains were more frequently observed in aggressive ATL than in indolent ATL, with significant differences between the 2 ATL subtypes at gains of 1q and 4q. An increased number of chromosomal imbalances was associated with a significantly shorter survival in all patients. A high number of chromosomal losses was associated with a poor prognosis in indolent ATL, whereas the presence of 7q+ was marginally associated with a good prognosis in aggressive ATL. Paired samples (ie, samples obtained at different sites from 4 patients) and sequential samples from 13 patients (from 6 during both chronic disease and acute crisis and from 7 during both acute onset and relapse) were examined by CGH and Southern blotting for HTLV-1. All but 2 paired samples showed differences on CGH assessment. Two chronic/crisis samples showed distinct results regarding both CGH and HTLV-1 integration sites, indicating clonal changes in ATL at crisis. In 11 patients, the finding of identical HTLV-1 sites and clonally related CGH results suggested a common origin of sequential samples. In contrast to chronic/crisis samples, CGH results with all acute/relapse sample pairs showed the presence of clonally related but not evolutional subclones at relapse, thereby suggesting marked chromosomal instability. In summary, clonal diversity is common during progression of ATL, and CGH alterations are associated with clinical course. (Blood. 2001;97:3875-3881)

The ALG-2/AIP-complex, a modulator at the interface between cell proliferation and cell death? A hypothesis

During the development of an organism cell proliferation, differentiation and cell death are tightly balanced, and are controlled by a number of different regulators. Alterations in this balance are often observed in a variety of human diseases. The role of Ca(2+) as one of the key regulators of the cell is discussed with respect to two recently discovered proteins, ALG-2 and AIP, of which the former is a Ca(2+)-binding protein, and the latter is substrate to various kinases. The two proteins interact with each other in a Ca(2+)-dependent manner, and the role of the complex ALG-2/AIP as a possible modulator at the interface between cell proliferation and cell death is discussed.

NMR solution structure of a complex of calmodulin with a binding peptide of the Ca2+ pump

The three-dimensional structure of the complex between calmodulin (CaM) and a peptide corresponding to the N-terminal portion of the CaM-binding domain of the plasma membrane calcium pump, the peptide C20W, has been solved by heteronuclear three-dimensional nuclear magnetic resonance (NMR) spectroscopy. The structure calculation is based on a total of 1808 intramolecular NOEs and 49 intermolecular NOEs between the peptide C20W and calmodulin from heteronuclear-filtered NOESY spectra and a half-filtered experiment, respectively. Chemical shift differences between free Ca(2+)-saturated CaM and its complex with C20W as well as the structure calculation reveal that C20W binds solely to the C-terminal half of CaM. In addition, comparison of the methyl resonances of the nine assigned methionine residues of free Ca(2+)-saturated CaM with those of the CaM/C20W complex revealed a significant difference between the N-terminal and the C-terminal domain; i.e., resonances in the N-terminal domain of the complex were much more similar to those reported for free CaM in contrast to those in the C-terminal half which were significantly different not only from the resonances of free CaM but also from those reported for the CaM/M13 complex. As a consequence, the global structure of the CaM/C20W complex is unusual, i.e., different from other peptide calmodulin complexes, since we find no indication for a collapsed structure. The fine modulation in the peptide protein interface shows a number of differences to the CaM/M13 complex studied by Ikura et al. [Ikura, M., Clore, G. M., Gronenborn, A. M., Zhu, G., Klee, C. B., and Bax, A. (1992) Science 256, 632-638]. The unusual binding mode to only the C-terminal half of CaM is in agreement with the biochemical observation that the calcium pump can be activated by the C-terminal half of CaM alone [Guerini, D., Krebs, J., and Carafoli, E. (1984) J. Biol. Chem. 259, 15172-15177].

Calmodulin-dependent protein kinase IV: regulation of function and expression

Calmodulin-dependent protein kinase IV (CaMKIV) is a key mediator of Ca2+-induced gene expression. This serine/threonine kinase is itself activated by a calmodulin kinase kinase. In the present contribution the gene structure, regulation of activity, the role in Ca2+-dependent gene expression, and the hormonal induction and controlled expression of CaMKIV during tissue development are reviewed.